Related Experiment Video
Updated: Aug 10, 2026
A Phenotyping Regimen for Genetically Modified Mice Used to Study Genes Implicated in Human Diseases of Aging
Published on: July 14, 2016
Warning: the use of heterogeneous mice may seriously damage your research
1MRC Toxicology Unit, University of Leicester, UK. mfwf1@le.ac.uk
Abstract:
Genetically heterogeneous (GH) mice and rats continue to be widely used in research even though the case for using isogenic strains has been argued repeatedly. The paper by Miller et al. in this issue appears to be the only one in the last 22 to attempt a scientific justification for the continued use of (a limited subset of) GH stocks. However, although they are to be commended for bravery, they fail to make their case. GH stocks represent poor material for controlled studies because genetic heterogeneity normally leads to phenotypic variability and a decline in experimental sensitivity. To counter this argument, Miller et al. claim that phenotypic variability may actually be smaller in GH animals than in their isogenic parents. Were this so (e.g., all mice being short lived, small, and aggressive), it is difficult to see how the use of such a stock could increase the generality of research results based on it, as claimed by Miller et al. Isogenic strains are a vital, proven, and powerful resource for biomedical research, and should be used in preference to GH stocks by all scientists who use laboratory rodents.
Insights
Genetically heterogeneous stocks in research are discouraged due to variability. Isogenic strains offer superior control and sensitivity for reproducible biomedical studies.
Area of Science:
- Biomedical Research
- Laboratory Animal Science
- Genetics
Background:
- Genetically heterogeneous (GH) stocks are frequently used in research despite arguments favoring isogenic strains.
- A recent paper by Miller et al. attempts to scientifically justify the use of limited GH stocks.
Discussion:
- GH stocks introduce phenotypic variability, reducing experimental sensitivity and compromising controlled studies.
- The claim that GH animals may have less variability than isogenic strains is critically examined.
- The argument that GH stocks increase the generality of research findings is challenged.
Key Insights:
- GH stocks are unsuitable for controlled studies due to inherent genetic heterogeneity and resulting phenotypic variability.
- Isogenic strains provide greater experimental control and sensitivity, leading to more reliable and reproducible research outcomes.
- The purported benefits of using GH stocks, such as increased generality, are not scientifically substantiated.
Outlook:
- The continued reliance on GH stocks in biomedical research warrants re-evaluation.
- Promoting the adoption of isogenic strains is crucial for advancing the quality and reproducibility of scientific findings.
- Future research should prioritize the use of isogenic strains for robust and generalizable results in laboratory rodent studies.
